Geant4  10.02.p01
G4MagHelicalStepper.hh
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28 // $Id: G4MagHelicalStepper.hh 93806 2015-11-02 11:21:01Z gcosmo $
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32 // class G4MagHelicalStepper
33 //
34 // Class description:
35 //
36 // Abstract base class for integrator of particle's equation of motion,
37 // used in tracking in space dependent magnetic field
38 
39 // It is used for a set of steppers which use the helix as a sort of
40 // 'first order' solution.
41 // - Most obtain an error by breaking up the step in two
42 // - G4ExactHelicalStepper does not provide an error estimate
43 
44 // History:
45 // - 05.11.98 J.Apostolakis Creation of new ABC
46 // --------------------------------------------------------------------
47 
48 #ifndef G4MagHelicalStepper_hh
49 #define G4MagHelicalStepper_hh
50 
51 #include <CLHEP/Units/PhysicalConstants.h>
52 
53 #include "G4Types.hh"
55 #include "G4Mag_EqRhs.hh"
56 #include "G4ThreeVector.hh"
57 
59 {
60  public: // with description
61 
63  virtual ~G4MagHelicalStepper();
64 
65  virtual void Stepper( const G4double y[], // VIRTUAL for ExactHelix - temporary
66  const G4double dydx[],
67  G4double h,
68  G4double yout[],
69  G4double yerr[] );
70  // The stepper for the Runge Kutta integration.
71  // The stepsize is fixed, equal to h.
72  // Integrates ODE starting values y[0 to 6]
73  // Outputs yout[] and its estimated error yerr[].
74 
75  virtual void DumbStepper( const G4double y[],
76  G4ThreeVector Bfld,
77  G4double h,
78  G4double yout[] ) = 0;
79  // Performs a 'dump' Step without error calculation.
80 
81  G4double DistChord()const ;
82  // Estimate maximum distance of curved solution and chord ...
83 
84  protected: // with description
85 
86  inline void LinearStep( const G4double yIn[],
87  G4double h,
88  G4double yHelix[]) const;
89  // A linear Step in regions without magnetic field.
90 
91  void AdvanceHelix( const G4double yIn[],
92  G4ThreeVector Bfld,
93  G4double h,
94  G4double yHelix[],G4double yHelix2[]=0); // output
95  // A first order Step along a helix inside the field.
96 
97  inline void MagFieldEvaluate( const G4double y[], G4ThreeVector& Bfield );
98  // Evaluate the field at a certain point.
99 
100 
101  inline G4double GetInverseCurve( const G4double Momentum, const G4double Bmag );
102  // Evaluate Inverse of Curvature of Track
103 
104  // Store and use the parameters of track :
105  // Radius of curve, Stepping angle, Radius of projected helix
106  inline void SetAngCurve(const G4double Ang);
107  inline G4double GetAngCurve()const;
108 
109  inline void SetCurve(const G4double Curve);
110  inline G4double GetCurve()const;
111 
112  inline void SetRadHelix(const G4double Rad);
113  inline G4double GetRadHelix()const;
114 
115 
116  protected: // without description
117 
118  // void MagFieldEvaluate( const G4double y[], G4double B[] )
119  // { GetEquationOfMotion()-> GetFieldValue(y, B); }
120 
121  private:
122 
125  // Private copy constructor and assignment operator.
126 
127  static const G4double fUnitConstant; // As in G4Mag_EqRhs.hh/cc where it is not used.
128  private:
129 
131 
132  // Data stored in order to find the chord.
136  // Data stored in order to find the chord.
138 
139 
140 };
141 
142 #include "G4MagHelicalStepper.icc"
143 
144 #endif /* G4MagHelicalStepper_hh */
void AdvanceHelix(const G4double yIn[], G4ThreeVector Bfld, G4double h, G4double yHelix[], G4double yHelix2[]=0)
virtual void Stepper(const G4double y[], const G4double dydx[], G4double h, G4double yout[], G4double yerr[])
virtual void DumbStepper(const G4double y[], G4ThreeVector Bfld, G4double h, G4double yout[])=0
CLHEP::Hep3Vector G4ThreeVector
G4double GetRadHelix() const
void MagFieldEvaluate(const G4double y[], G4ThreeVector &Bfield)
G4double GetCurve() const
void LinearStep(const G4double yIn[], G4double h, G4double yHelix[]) const
G4MagHelicalStepper(G4Mag_EqRhs *EqRhs)
G4double GetInverseCurve(const G4double Momentum, const G4double Bmag)
void SetRadHelix(const G4double Rad)
void SetAngCurve(const G4double Ang)
G4MagHelicalStepper & operator=(const G4MagHelicalStepper &)
void SetCurve(const G4double Curve)
double G4double
Definition: G4Types.hh:76
G4double GetAngCurve() const
G4double DistChord() const
static const G4double fUnitConstant